High tension cable



Dec. 8, 1936. J. FORSTER HIGH TENSION CABLE Filed Aug. 23, 1932 INVENTO.R- JbsPfl/Z foraier wkmb Patented Dec. 8, 1936 UNITED STATES PATENT OFFICE.

Application August 23, 1932, Serial No. 630,025 In Austria August 27, 1931 12 Claims. (Cl. 173-266) This invention relates to cables in which outer shells of conductors are supported on hollow central devices for the transmission of electrical energy at extremely high voltages.

Heretofore high tension cables of comparatively large, diameter have been proposed for counteracting corona effect or so called glimmer phenomena, which entail high losses. These cables, some of which included conductors having air spaces, and on which wires of different gages were stranded, have been characterized by certain disadvantages, in that they were not fully equal to the stresses imposed thereon, especially structural stresses, as during cable laying, and

for this reason they very easily suiiered deterioration, or injury. Without loss of strength, as presently further stated, comparatively light cables may be constructed according to this invention.

One of the objects of this invention is to overcome the said disadvantages. The present organization includes a layer or shell of conducting strands with a central air space, and a novel feature of the invention resides in a supporting or propping device or core in the air space for carrying the strands.

The said device includes a helical tape or element of conductive material, the turns of which are spaced apart, although not necessarily so.

By utilizing a plural number of these elements the compressive strength of the support, its resistance to deformation, and the tensile strength of the organization are greatly increased, to secure another object of the invention.

Although particularly suited for overhead wiring, where the distance between the towers or supports may be very great, the present cable, as when insulated, may be used with other constructions.

With the above indicated objects in view, and

others which will hereinafter appear, the essential features of the invention are herein clearly described, and illustrated in the accompanying drawing, in which:

Fig. l is a cross sectional view of a cable consisting of cooperating coiled bands, the turns of which form segments of a cylinder, whereon one or more layers or shells of conductors are mounted.

Fig. 2 is a lateral elevational view of the structure shown in Fig. 1.

Fig. 3 is a cross sectional view of a modified form of cable.

Fig. 3a is a cross-sectional view of a modified form of one of the conductors of Fig. 3,

Fig. 4 is a fragmentary elevational view of the structure illustrated in Fig. 3.

Fig. 5 is a cross sectional view of a cable in which other layers or shells are shown external to the conductors, and

Fig. 6 is a lateral elevational view of the structure illustrated in Fig. 5.

In Figs. 1 and 2 the supporting device for the outer shell of conductors 11 or 12 includes three coiled bands or ribbons, the turns of which, each 10 designated a, as shown in Figs. 1, 2, 5, and 6, are of such cross sectional shape as to form segments of a cylinder. The turns of the coils, which may be of suitable copper, or other metal, such as steel, are spaced apart, and the turns of one coil 15 are disposed opposite the spaces between the turns of adjacent coils.

In order to hold a group of the coils together especially before or while stranding the conductors thereon, a narrow binding strip b, which may 20 be of any suitable material, ispassed around the group. The turns of the supporting bands are all disposed in one direction, as illustrated, and the binding strip may pass over the aforesaid spaces, its turns, which may have any convenient pitch 25 interval, are disposed in the opposite direction.

Although three of the hands a, and a circular organization, are represented in the drawing, any other number of bands may be used, and the circular form need not necessarily be adhered to. 30 A single band a, or two bands, or a greater number than that which is illustrated may be used; the outline of the cable may diiier from the form shown, since it may be elliptical, for example;

and the said bands may be of polygonal or other cross sectional form, rather than the particular segmental arrangement illustrated.

The conductors l or shell, (referring to Fig. 3 and Fig. 6) instead of being solid may be hollow, and any number of layers or circular rows of 40 these conductors, another oi which (Fig. 2) is represented in part at Z2, may be used. The turns .of the layers of these conductors, which are mounted on .the supporting device by a stranding machine, are of relatively long pitch, 5 so that it is immaterial in which direction they are disposed, relative to the direction of the turns of the bands (1, the latter being of short pitch.

Each of the turns of the cooperating spirally wound supporting bands a is provided with two 5 straight portions, as shown adjacent the axis of the cable, and as these respective portions engage, while the curves of the interposed outer portions are positioned on lines having their centers on said axis, the arrangement results in 55 practically continuous cylindrical outer turns, there being only slight spaces, as at present shown, between each pair of the coacting supporting members, adjacent the shell of conductors. The structural elements within the hollow e (Fig. 5) of the cable are therefore very limited or reduced in character, to render the supporting device exceptionally strong and light.

Mounted on the shell formed by the conductors, as Z in Fig. 5, is insulating material 1, in the present instance represented as laminated paper, the number of layers of which may be accord ing to requirements; and outside of these layers is a protective lead sheath in, hereinafter further referred to.

As illustrated in Fig. 3 the supporting elements or ribbons z for the shell of conductors are of circular cross section. Said elements are also in the form of strips, which are spirally wound, and the turns of these strips are also spaced apart.

This latter arrangement provides spaces of considerable dimension between the pairs of elements 2 and the shell; and in each of the said spaces is disposed another conductor t, which may be bare or insulating material t1 may be provided thereon. Instead of said conductors t, 1' may provide spiral metal windings such as the winding 22 (Fig. 3a), one winding instead of each conductor, and these windings v or conductor t also engage the inner periphery of the outer shell of conducting wires.

The aforesaid lead sheath may be compounded or armoured, and the hollow spaces e may serve as oil passages, in which the fluid may be circulated under pressure.

Having ascertained and now described the nature of my said invention and the manner in which the same is to be performed, what I claim is:

l. A compound electrical conductor comprising in combination a hollow cylindrical shell of spirally disposed metallic elements, and means disposed within the hollow of said shell in supporting relation with said elements; said means including spirally wound metal strips which form conductors of large diameter and circular cross section, said conductors having mutually engaging portions disposed adjacent the axis of said shell and other portions which engage the inner periphery of said shell; and conductors disposed in the spaces between said circular conductors and said inner periphery.

2. A cable including, in combination, a bundle of longitudinally disposed supports, each support comprising a ribbon of metal helically coiled with convolutions disposed in edgewise spaced relation, the convolutions lying in a common tubular surface longitudinal to the cable to form substantially laterally engaging substantially parallel hollow supports of large diameter; a shell of circular cross-section comprising conductor wires wound spirally around said bundle and supported thereby and leaving spaces of approximately triangular cross-section between the supports and the surrounding shell; and round conductors arranged longitudinally in said space and substantially engaging said supports and shell; the diameter of the round conductors being much smaller than that of said supports; whereby the convolutions of said supports may be capable of such elongation and shortening as to facilitate bending of the cable.

3. A cable as in claim 2 said round conductors being rod like and of continuous C 'Q Section and covered with insulation.

4. A cable as in claim 2, said round conductors being formed by a helical strip.

5. A cable comprising in combination a hollow tubular shell of electrical conductive material, a core disposed within the hollow and including metal bands which are formed into partly flattened helices having open axes; each of said helices having turns which include radially disposed straight portions, the straight portions of one helice being engaged against the straight portions of an adjoining helice, and coacting interposed portions of relatively large area engaging the inner face of said shell.

6. A cable comprising in combination a hollow tubular shell including helically disposed electrical conductors having turns of relatively long pitch, a second conductor disposed in the hollow of the first mentioned conductor and consisting of a helically wound band the turns of which have short pitch, said band having its periphery partly engaging the inner face of the shell, and a third conductor like the second mentioned conductor and having its turns alternating with the second mentioned turns, said third conductor being also peripherally engaged against the first mentioned periphery and against said face.

'7. A core for a hollow cable, comprising a pair of bands of electrical conductive material, which bands are formed into two laterally engaging helices having turns of short pitch, and a band of relatively long pitch wound around said helices.

8. A core for a cable having an outer shell of electrical conductors, comprising metal bands which are wound into helices having individual hollow longitudinal centers the axes of which are spaced apart, said helices having their turns disposed in the same direction, and a metal band wound in the opposite direction around said helices to hold the latter together.

9. A cable comprising in combination with a hollow tubular shell including helically disposed mutually contacting electrical conductors having turns of a certain pitch, and an electrically conductive core disposed within the hollow of said shell in supporting relation therewith, said core including a plurality of ribbon-like bands which are formed into laterally engaging helices the turns of which have their opposite edges aligned longitudinally of the cable, the turns of said helices having a pitch difiering from the pitch of the turns of the conductors of said shell, the individual turns of the respective helices having their opposite edges disposed in adjoining relation, and the medial helical lines of the turns of one of said helices being substantially opposite the adjoining edges of the turns of the next helix. 10. A cable comprising in combination with a hollow tubular shell including helically disposed conductors the turns of which are of relatively long pitch, a core disposed within the hollow of said shell and including ribbon-like metal bands which are formed into laterally engaging helices the turns of which are of short pitch, said second turns having their opposite edges aligned longitudinally of the cable, there being spaces between the adjoining edges of the respective turns of the helices, the turns of one of said helices being disposed substantially opposite the spaces between the edges of the turns of the next helix, and there being parts of the peripheries of said helices engaged against the inner face of said shell, whereby to increase the pliability of the cable.

11. In a cable, the combination of a hollow tubular shell of helically disposed electrical conductors, sheet insulating material wrapped 15 aoeasoe 3 around saidshell; a metal sheath covering the insulation, and a substantially hollow metal core disposed within the hollow of said shell, said core including a plurality of bands which are wound into separate helices having independent open axes, each helix consisting of one band, said helices having parts of their peripheries disposed in mutual engagement, and there being parts of the peripheries of said helices engaging the inner face of said shell.

12. In a cable, the combination 01' a hollowtubular shell of helically disposed electrical conducting wires, a layer of-insulating material covering said wires, a sheath of bendable metal covs ering the insulation, and a substantially hollow metal core disposed within the hollow or said shell in supporting relation with the wires; said core including bands which are wound into helices having open axes of certain large diameter,

said helices having parts of their peripheries 5 mutually engaged, other parts of said peripheries being engaged against the inner face of said shell; and helices of small diameter having parts oi their peripheries engaged against the first peripheries, parts of the peripheries of said second 10 mentioned helices being also engaged against said face, said second helices also having open axes.

' JOSEPH mass-m. 1s 

